Production of organic phosphonyl halide



PRODUCTION OF ORGANIC PHOSPHONYL HALIDE Jack Kwiatek, North Arlington, N.J., assignor to The M. W. Kellogg Company, Jersey City, N .l

No Drawing. Application October 30, 1953 Serial No. 389,504

31 Claims. (Cl. 260-543) This invention relates to a method for the manufacture of an organic phosphonyl halide. In one aspect the invention relates to the. production of alkyl phosphonyl halides, including acyclic and alicyclic alkyl phosphonyl halides. In one of its more particular aspects, the invention relates to the production of methane phosphonyldichloride.

The organic phosphonyl halides and especially methane phosphonyl dichloride are much in demand as intermediate chemical reactants for the production of more complex organic phosphorus compounds, such as the corresponding esters, free acids and amides by conventional methods, which are useful as fungicides, insecticides, pharmaceuticals, petroleum additives to improve the sta-. bility and quality of lubricating oils, and polymer additives. The conventional method for producing the organic phosphonyl halides is illustrated by the following reactions:

oatort It has now' been found that improved yields of organic phosphonyl halides may be obtained by a direct process which comprises reacting a phosphorus trihalide and an organic compound selected from at least one of the group consisting of the organic ethers, esters, acetals and ketals in the presence of particular catalysts.

An object of this invention is to provide a cheaper and more direct method of producing organic phosphonyl halides.

Still another object is to provide a process for producing organic phosphonyl halides in improved yields and selectivity.

Another object of this invention is to provide a method for producing methane phosphonyl dichloride with the minimum formation of by-products and the maximum utilization of reactants.

Various other objects and advantages of the present invention will become apparent to those skilled in the art from the accompanying description and disclosure.

2,882,308 Patented Apr. 14, 1959 ice where R is an organic radical, preferably an alicyclic or acyclic alkyl radical including the substituted radicals, such as an aralkyl radical or a halogen substituted acyclic or alicyclic alkyl radical, and X is any of the halogens (Br, Cl, I, F) and the Xs may be the same or dilferent halogen atoms, is produced by directly reacting a phos-' phorus halide, preferably a phosphorus trihalide, having halogens corresponding to the halogens of the desired product with an organic compound of the formula: RO--R' in which R is an organic radical and is the same as the R of the general formula for the organic phos phonyl halide and R is a radical containing an organic group, in the presence of a catalyst comprising iodine. The organic phosphonyl halide produced may be recovered directly from the reaction mixture by conventional methods, such as distillation, or may be reacted with other compounds to form derivatives thereof and the derivative recovered.

Various phosphorus trihalides may be employed, such as phosphorus trifluoride, phosphorus trichloride, phosphorus tribromide, phosphorus triiodide and diphosphorus tetra-iodide; and the mixed halide phosphorus trihalides, such as fiuoro phosphorus dichloride, difluoro phosphorus chloride, fluoro chloro phosphorus bromide, dichloro phosphorus iodide and dichloro phosphorus bromide. The particular phosphorus trihalide employed depends upon the ultimate product desired. When producing an organic phosphonyl dichloride, phosphorus trichloride is preferred.

The organic compounds of the formula ROR to be reacted with the phosphorus halide include the ethers, esters, acetals and ketals and are preferably those compounds in which R is an alicyclic or acyclic alkyl radical having not more than eight carbon atoms and R is an organic radical, preferably having a continuous carbon skeleton and not more than 8 carbon atoms, i.e., all carbon attached together, -CCC. Mixtures of two or more difierent organic compounds (R-O-R) may be reacted with the phosphorus trihalide without de- I parting from the scope of this invention. In case R or R are halogen substituted radicals the halogen may be any of the group F, Cl, I and Br, however, chlorine and bromine are preferred.

The preferred organic ethers are selected from the group consisting of the acyclic and alicyclic alkyl ethers including the substituted acyclic alkyl ethers such as the halo, nitro, cyano and aryl substituted ethers. of ethers are the simple symmetrical ethers, such as dimethyl ether, diethyl ether; dicyclohexyl ether; dibenzyl ether; beta, beta'-dichloro diethyl ether; and beta, betaoxy diproprionitrile. The simple unsymmetrical ethers may also be employed but, with the exception of the mono-alpha halogenated alkyl ethers, the unsymmetrical ethers lead to the formation of mixed products corresponding to the diflerent alkyl or cycloalkyl radicals of the ether. Of such unsymmetrical ethers, examples are:

methyl ethyl ether, methyl n-bu'tyl ether, ethyl n-propyl Examples corresponds to the R group of the general formula and R" is hydrogen or an alkyl radical and the R group is found in the final product, are particularly good substituted others which may be used; examples are chloromethyl methyl ether; bromo methyl ethyl ether, alpha-chloro ethyl propyl ether and bromo methyl isoamyl ether. X of the above formula is a halogen (Cl, F, Br, 1). instead of using simple ethers containing only one ether linkage, poly ethers, such as polyoxymethylene, polyoxyethylene and polyoxypropylene alcohols may be employed in this invention.

Examples of the esters include the mono esters, the poly esters and the ortho esters. Preferred mono esters are: methyl formate, methyl acetate, hutyl acetate, benzyl acetate and methyl propionate. Suitable ortho esters include trimethyl ortho formate, trimethyl ortho acetate, dimethyl cyclobutyl ortho acetate and trimethyl ortho benzoate. Examples of polyesters are: dimethyl oxalate, dimethyl phthalate and dimethyl adipate. Other esters include the polyesters of inorganic acids, such as dimethyl carbonate, dimethyl sulfate, diethyl sulfate, trimethyl borate, tributyl borate and triethyl phosphate.

Suitable acetals include dimethyl formal, diethyl formal, dimethyl acetal and diethyl benzal. Examples of ketals for use in this invention are: dimethyl ketal of acetone and cyclohexanone.

The reaction of this invention is carried out in the presence of a catalyst containing iodine. Examples of suitable iodine-containing catalysts which may be used in accordance with this invention are: metal iodides such as nickel iodide, zinc iodide, cobalt iodide, sodium iodide, aluminum iodide and manganese iodide; phosphorus iodides such as phosphorus di-iodide and phosphorus triiodide; phosphonium iodides such as trimethyl phosphonium di-iodide; alkyl iodides such as methyl iodide; free iodine; and a metal chlorophosphine, such as nickel tetrakistrichlorophosphine, in combination with a metal iodide such as nickel iodide. Generally the catalyst is em ployed in an amount between about 0.001 mole to about 1 mole per mole of organic ether, the preferable amount being between about 0.005 mole and about 0.5 mole per mole of ether.

A typical equation representing the reaction of this invention is:

where Catalyst compri sing iodine where R and R are organic radicals and X is a halogen atom, as previously discussed. Both R and R and X may be the same or different atoms of their respective groups. The above reaction is-carried out generally at a temperature above about room temperature (20 C.) and below the decomposition temperature of the reactants. Generally the temperature will be not higher than about 500 C. The reaction is preferably carried out in the liquid phase and this is accomplished by employing sufiicient pressure to maintain the reactants in liquid phase condition in the reaction zone at the temperature employed. Conveniently, the reaction is carried out under autogenous conditions of pressure. The preferred temperature range for liquid phase operations at elevated pressures is between about 175 C. and about 275 C.

The ratio of phosphorus trihalide and organic reactant may be varied over relatively'wide limits but it is preferable to employ between about equimolar amounts of both reactants and about a four fold molar excess of phosphorus trihalide reactant. Similarly, the time of reaction may vary over relatively wide limits, such as minutes to 20 hours, the preferable time of reaction being about one hour to about 15 hours.

The reaction of this invention may be conducted as a multistage reaction, and preferably as a two-stage reaction. Conducting the reaction in such a stepwise manner consists of reacting in the first step of the reaction the phosphorus trihalide and the organic reactant in the presence of the catalyst comprising iodine, the second and subsequent steps then consist of treating the total crude product obtained in the first step with additional amounts of the same reactants used in the first step with or without the addition of more catalyst. In so conducting the reaction in this step-wise manner improved yields of organic phosphonyl halides are obtained by using smaller amounts of catalyst as compared to the amount of catalyst needed when the reaction is conducted as a one-stage reaction. H

' The reaction may also be carried out in batchwise or continuous systems without departing from the scope of this invention. The reaction may be effected in the presence of liquid diluents, such as chloroform, xylene, benzene, and cyclohexane, in which the reactants are dissolved, or dispersed by mechanical agitation or by conventional emulsifying agents.

The iodine which may be present upon completion of the reaction is conveniently removed by treating the crude product with mercury followed by removal of mercury iodide salts by filtration. The products of the reaction are further purified by conventional techniques, such as distillation or crystallization depending upon the physical nature of the products. The organic phosphonyl halides may be isolated as such or they may be hydrolyzed to the corresponding phosphonic acids which may then be converted to various ester derivatives, or the phosphonyl halides may be converted directly to a desired type' ester by conventional methods. The products are identified by the usual methods, such as determination of boiling point and other such physical properties, determination of infrared absorption spectra, percent composition analysis, mass spectrometer analysis, etc.

It is to be understood that the choice of temperature of reaction, contact time, molar quantities of reactants and catalyst to be preferred in any instance will depend upon such factors as the starting materials employed and the product desired, and that the procedure for the isolation and purification of desired products will be dependent upon the physical nature of the products.

The following examples are offered as a better understanding of the present invention and of the reaction of phosphorus trichloride with various organic compounds to produce methane phosphonyl dichloride, but the examples are not to be considered as unncessarily limiting to the present invention. Although the following examples describe the preparation of methane phosphonyl dichloride, other organic phosphonyl halides maybe prepared similarly by the process of this invention, a few illustrative examples of which are: methane phosphonyl dibromide, cyclohexane phosphonyl dichloride, ethane phosphonyl dichloride, iso-propane phosphonyl dichloride, benzyl phosphonyl dichloride, ethane phosphonyl dibromide and 2-chloro ethane phosphonyl dichloride.

Example 1 A 200 ml. steel pressure bomb was charged with 78.5 ml. (0.9 mole) of phosphorus trichloride, 33.0 grams (0.72 mole) of dimethyl ether and 18.8 grams (0.06 The bomb was closed, placed form, shaken with mercury and filtered to remove the mercury iodide salts. After evaporation of the chloroform the residual liquid was subjected to distillation at elevated temperatures and atmospheric pressure to obtain an impure fraction boiling at 158 C. to 185C. This fraction was found to contain a substantial amount of methane phosphonyl dichloride and a small amount of dimethyl phosphonyl chloride.

Example 2 Example 3 A 200 ml. steel pressure bomb was charged with 78.5 ml. (0.9 mole) of phosphorus trichloride, 26.6 grams (0.58 mole) of dimethyl ether and 19.2 grams (0.06 mole) of zinc iodide. The procedure of Example 1 was repeated except that the reaction time at 250 C. was 5.3 hours. obtained and was found to contain a substantial amount of methane phosphonyl dichloride and some dimethyl,

phosphonyl chloride.

Example 4 A 200 ml. steel pressure bomb was charged with 0.68 mole of phosphorus trichloride, 0.68mole (31.2 grams) of dimethyl ether, 0.056 mole of nickel tetrakistrichlorophosphine and 0.004 mole (1.36 grams) of'nickel iodide. The bomb was then closed, placed in a reciprocating shaker, heated to 250 C. and held at this temperature for seven hours. The total crude product inthe bomb was transferred to a distillation flask and heated at atmospheric pressure to obtain a liquid fraction boiling at 15 8 C. to 190 C. This fraction contained a substantial amount of methane phosphonyl dichloride and a small amount of dimethyl phosphonyl chloride.

Example 5 the mercury iodide salts, and redistilled at atmospheric.

pressure to obtain an impure fraction boiling at 150 C. to 185 C. and containing a substantial amount of methane phosphonyl dichloride.

Example 6 A 200 ml. steel pressure bomb was charged. with 106 ml. (1.2 mole) of phosphorus trichloride, 35 ml. (0.4 mole) of chloromethyl methyl ether and 63.8 grams (0.2 mole) of zinc iodide. The procedure of Example 1 was repeated. A fraction with a boiling point of 150 C. to 165 C. consisted chiefly of methane phosphonyl dichloride. This fraction was treated once again with mercury to remove the last traces of iodine. The yield of methane phosphonyl dichloride, obtained as white crystals, was 35 percent of the theoretical yield on the basis of the amount of chloromethyl methyl ether used.

Example 7 A 200 ml. steel pressure bomb was charged with 106 A fraction boiling at 155 C. to 180 C. was

ml. 1.2 moles) of phosphorus trichloride, 35 ml. (0.4

mole) of dimethyl formal and'24.4 grams (0.1 mole) of' The procedure of Example 1' phosphorus di-iodide. was repeated. A fraction boiling at 157 C. to 169 C. was obtained which consisted chiefly of methane phosphonyl dichloride. dichloride was 25 percent of the theoretical yield on the basisof the amount of dimethyl formal used.

Example 8 A 200 m1. steel'pressurebomb was charged with 106 ml. (1.2 moles) of phosphorus trichloride, 35 ml. (0.4

mole) of dimethyl formal and 27.4 grams (0.067 mole) of phosphorus tri-iodide. The procedure of Example 1 was repeated. A fraction boiling at 160 C. to 172 C. consisted chiefly of methane phosphonyl dichloride.

of the theoretical yieldon the basis of the amount of:dimethyl formal employed.

Examp 9 A 200 ml. steel pressure bomb was charged'withj106: ml. (1.2 moles) of phosphorus trichloride, 35 ml. (0.41

Example 10 A 200 ml. steel bomb was charged with 106 ml. (1.2

moles) of phosphorus trichloride, 35 ml. (0.4 mole) of" dimethyl formal and 24.7 grams (0.08 mole) of manganese iodide. The procedure of Example 1 was repeated. A fraction boiling at 160 C. to 168 C. was obtained and consisted chiefly of methane phosphonyl dichloride. The yield of methane phosphonyl dichloride was 51 percent of theoretical yield on the basis of the amount of dimethyl formal used.

Example 11 A 200 ml. steel pressure bomb was charged with 106' ml. (1.2 moles) of phosphorus trichloride, 35.4 ml. (0.4 mole) of dimethyl formal and 62.5 grams (0.2 mole) of nickel iodide. The procedure of Example 1 was repeated except that the temperature of reaction was decreased to 225 C. A fraction boiling at 150 C. to 168 C. was obtained and found to consist mainly of methane phosphonyl dichloride. The yield of methane phosphonyl dichloride was 61 percent of the theoretical yield on the basis of the amount of dimethyl formal employed.

Example 12 A 200 ml. steel pressure, bomb was charged with 21 ml. (0.24 mole) of phosphorus trichloride, 6.09 grams. (0.08 mole), of dimethyl formal and 12.5 grams (0.04 mole) of nickel iodide. The bomb was then closed, placed on a reciprocating shaker, heated to 250 C. and held at this temperature for 7 hours. The bomb was then cooled and vented to atmospheric pressure and charged further with ml. (0.96 mole) of phosphorus trichloride and 24.3 grams (0.32 mole.) of dimethyl formal. The bomb was then closed, placed in the reciprocating shaker and heated at 250 C. foran additional seven hours. The total crude product in the bomb was transferred to a distillationflask and heated at, atmospheric pressure. Two liquid fractions were obtained: the first fraction had a boiling point of 40 C. to C.; and the second fraction had a boiling point of 120 C. to 204 C. The boiling fraction was The yield of methane phosphonyl Theyield of methane phosphonyl dichloride was 47 percent form, shaken with mercury and filtered to remove the mercury iodide salts. After removal of the chloroform from the high boiling fraction, this fraction was further purified by distillation at elevated temperatures and atmospheric pressure. A liquid fraction having a boiling point of 145 C. to 167 C. contained 41.9 grams of methane phosphonyl dichloride as determined by mass spectrometer analysis. This weight of methane phosphonyl dichloride corresponds to 83 percent of the theoretical yield on the basis of the total amount of dimethyl formal employed.

Although the invention has been described with relation to specific reaction conditions and operating techniques, various modifications and alterations may become apparent to those skilled in the art without departing from the scope of this invention.

Having described my invention, I claim:

1. A process for the production of an organic phosphonyl halide which comprises reacting a trivalent phosphorus halide and an organic compound of the formula R--OR' where R is an alkyl radical having not more than eight carbon atoms and R is a radical having not more than 8 carbon atoms selected from the group consisting of an unsubstituted alkyl radical, a haloalkyl radical, a

( )-O-alkyl radical and a --CH -.O-alkyl radical, in the presence of a catalyst comprising iodine at a temperature of at least 20 C. to produce an organic phosphonyl halide.

2. The process of claim 1 in which the said catalyst comprising iodine is a metal iodide.

3. The process of claim 2 in which the said metal iodide is nickel iodide.

4. The process of claim 2 in which the said metal iodide is zinc iodide.

5. The process of claim 2 in which the said metal iodide is cobalt iodide.

6. The process of claim 1 in which the said catalyst comprising iodine is a phosphorus iodide.

7. The process of claim 6 in which the said phosphorus iodide is phosphorus di-iodide.

8. The process of claim 1 in which the said catalsyt comprising iodine is free iodine.

9. The process of claim 1 in which said phosphorus trihalide is phosphorus trichloride.

10. The process of claim 1 in which said phosphorus trihalide is phosphorus tribromide.

11. The process of claim 1 in which said phosphorus trihalide is phosphorus triiodide.

12. The process of claim 1 in which said phosphorus trihalide is phosphorus trifiuoride.

13. The process of claim 1 in which said phosphorus trihalide is fluoro phosphorus dichloride.

14. The process of claim 1 in which the compound of the formula R-OR' is an ether.

15. The process of claim 14 in which said ether is dimethyl ether.

16. The process of claim 14 in which said ether is chloromethyl methyl ether.

17. The process of claim 1 in which the compound of the formula RO.R' is an ester.

18. The process of claim 17 in which. said ether is dimethyl carbonate.

19. The process of claim 1 in which the compound of the formula ROR' is an acetal.

20. The process of claim 19 in which said acetal is dimethyl formal.

'21. A'process for the production of an organic phosphonyl halide which comprises reacting a phosphorus trihalide and an organic compound of the formula R O.R' where R is an alkyl radical having not more than eight carbon atoms and R is a radical having not more than 8 carbon atoms selected from the group consisting of an unsubstituted alkyl radical, a haloalkyl radical, a

-iJ0-a1k 1 radical and a CH fiO=alkyl radical in the presence of a catalyst comprising iodine at a temperature between about 20 C. and about 500 C. for a period of time between about 10 minutes and about 20 hours to produce an organic phosphonyl halide of the formula 0 rai -x. in which X is a halogen atom.

22. A process for the production of methane phosphonyl dichloride which comprises reacting phosphorus trichloride and dimethyl ether in the presence of a catalyst comprising iodine at a temperature between about C. and about 275 C. for a residence time between about 1 and about 15 hours to produce methane phosphonyl dichloride, and recovering the methane phosphonyl dichloride as a product of the process.

23. The process of claim 22 in which the said catalyst is nickel iodide.

24. The process of claim 22 in which the said catalyst is cobalt iodide.

25. The process of claim 22 in which the said catalyst is zinc iodide.

26. A process for the production of methane phosphonyl dichloride which comprises reacting phosphorus trichloride with dimethyl carbonate in the presence of nickel iodide as a catalyst at a temperature between about 175 C. and about 275 C. for a residence time between about 1 and about 15 hours to produce methane phosphonyl dichloride and recovering the methane phosphonyl dichloride as a product of the process.

27. A process for the production of methane phosphonyl dichloride which comprises reacting phosphorus trichloride and chloromethyl methyl ether in the presence of zinc iodide as a catalyst at a temperature between about 175 C. and about 275 C. for a residence time between about 1 and about 15 hours to produce methane phosphonyl dichloride, and recovering the methane phosphonyl dichloride as a product of the process.

28. A process for the production of methane phosphonyl dichloride which comprises reacting phosphorus trichloride with dimethyl formal in the presence of a catalyst containing iodine at a temperature between about 175 C. and 275 C. for a residence time between about 1 and about 15 hours to produce methane phosphonyl dichloride, and recovering as a product of the process the methane phosphonyl dichloride thus produced.

29. The process of claim 28 in which the said catalyst is nickel iodide.

30. The process of claim 28 in which the said catalyst is phosphorus di-iodide.

31. The process of claim 28 in which the said catalyst is free iodine.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Kosolapoff: Organo-phosphorus Compounds (August 1950), pages 48 and 62.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,882,308 April 14, 1959 Jack Kwiatek It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 8, line 8, for the formula "-SI-I -6== alkyl" read ei-fi walkyl Signed and sealed this ZUtZQday of October 1959.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Ofiicer Commissioner of Patents 

1. A PROCESS FOR THE PRODUCTON OF AN ORGANIC PHOSPHONYL HALIDE WHICH COMPRISES REACTING A TRIVALENT PHOSPHORUS HALIDE AND AN ORGANIC COMPOUND OF THE FORMULA R-O-R'' WHERE R IS AN ALKYL RADICAL HAVING NOT MORE THAN EIGHT CARBON ATOMS AND R'' IS A RADICAL HAVING NOT MORE THAN 8 CARBON ATOMS SELECTED FROM THE GROUP CONSISTING OF AN UNSUBSTITUTED ALKYL RADICAL, A HALOALKYL RADICAL, A 